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<sect1 xml:id="Logging" version="5.0" xmlns="http://docbook.org/ns/docbook"
       xmlns:xi="http://www.w3.org/2001/XInclude"
       xmlns:xlink="http://www.w3.org/1999/xlink"
       xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
       xsi:schemaLocation="http://docbook.org/ns/docbook http://www.docbook.org/xml/5.0/xsd/docbook.xsd
       http://www.w3.org/1999/xlink http://www.w3.org/1999/xlink.xsd">
    <title>Logging Configuration</title>
    <para>Hazelcast has a flexible logging configuration and doesn't depend on any logging framework except JDK logging.
        It has in-built adaptors for a number of logging frameworks
        and also supports custom loggers by providing logging interfaces.
    </para>
    <para>To use built-in adaptors you should set
        <code>hazelcast.logging.type</code>
        property to one of
        predefined types below.
        <itemizedlist>
            <listitem>
                <para><emphasis role="bold">jdk:</emphasis>JDK logging (default)
                </para>
            </listitem>
            <listitem>
                <para><emphasis role="bold">log4j:</emphasis>Log4j
                </para>
            </listitem>
            <listitem>
                <para><emphasis role="bold">slf4j:</emphasis>Slf4j
                </para>
            </listitem>
            <listitem>
                <para><emphasis role="bold">none:</emphasis>disable logging
                </para>
            </listitem>
        </itemizedlist>

        You can set
        <code>hazelcast.logging.type</code>
        through configuration xml, configuration API or JVM system property.
        <itemizedlist>
            <listitem>
                <para>
                    <emphasis role="bold">Configuration xml</emphasis>
                </para>
                <para>
                    <programlisting language="xml">
&lt;hazelcast xsi:schemaLocation="http://www.hazelcast.com/schema/config 
    http://www.hazelcast.com/schema/config/hazelcast-config-2.5.xsd"
    xmlns="http://www.hazelcast.com/schema/config"
    xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"&gt;

    ....

    &lt;properties&gt;
        &lt;property name="hazelcast.logging.type"&gt;jdk&lt;/property&gt;
        ....
    &lt;/properties&gt;
&lt;/hazelcast&gt;</programlisting>
                </para>
            </listitem>
            <listitem>
                <para>
                    <emphasis role="bold">Configuration API</emphasis>
                </para>
                <para>
                    <programlisting language="java">
Config cfg = new Config() ;
cfg.setProperty("hazelcast.logging.type", "log4j");
                    </programlisting>
                </para>
            </listitem>
            <listitem>
                <para>
                    <emphasis role="bold">System Property</emphasis>
                </para>
                <para>
                    <orderedlist>
                        <listitem>
                            <para>Using JVM parameter:
                                <literal>java -Dhazelcast.logging.type=slf4j</literal>
                            </para>
                        </listitem>
                        <listitem>
                            <para>Using System class:
                                <literal>System.setProperty("hazelcast.logging.type", "none");</literal>
                            </para>
                        </listitem>
                    </orderedlist>
                </para>
            </listitem>
        </itemizedlist>
    </para>

    <para>To use custom logging feature you should implement
        <code>com.hazelcast.logging.LoggerFactory</code>
        and
        <code>com.hazelcast.logging.ILogger</code>
        interfaces and set system property
        <literal>hazelcast.logging.class</literal>
        to
        your custom
        <code>LoggerFactory</code>
        class name.
        <programlisting language="java">java -Dhazelcast.logging.class=foo.bar.MyLoggingFactory</programlisting>
    </para>

    <para>
        You can also listen to logging events generated by Hazelcast runtime by registering <literal>LogListener</literal>s to<literal>LoggingService</literal>.
        <programlisting language="java">
LogListener listener = new LogListener() {
    public void log(LogEvent logEvent) {
        // do something
    }
}
LoggingService loggingService = Hazelcast.getLoggingService();
loggingService.addLogListener(Level.INFO, listener):
        </programlisting>
        Through the
        <literal>LoggingService</literal>
        you can get the current used ILogger implementation and log your own messages too.
    </para>
</sect1>